This is a request for funds to enable young investigators to attend a symposium on Mechanisms of Spatial Vision at the Center for Visual Science in June of 1984. Recently, much effort has been directed toward understanding the psychophysical and physiological mechanisms that underlie the exquisite spatial discriminations characteristic of human vision. The meeting will provide an opportunity to integrate new findings from different areas: 1) the contribution to visual performance of the optics of the eye, the photoreceptor mosaic, and the receptive fields of neurons at various levels of the visual system; 2) the impact of spatial sampling by arrays of detectors, and of probability summation between these detectors; 3) the mechanisms underlying vernier and stereoacuity nd interpolative processes in motion perception; 4) changes in spatial vision with retinal eccentricity, and the representation of the visual field in the cortex.